Such boats are often overcrowded (Photo: Tommy Trenchard)
Police in Sierra Leone say 221 people are missing after a boat capsized on Tuesday with 268 people on board - many more than initially reported.
Officials suspect the boat was carrying twice as many people as it was intended for, and they did not have lifejackets.
"The rules were violated... and people died," Information Minister Alhaji Ibrahim Ben Kargbo told the BBC.
The authorities had said there were 150 people on board, but changed the figure after seeing passenger lists.
Another official has suggested there could have been more than 300 people on board.
The BBC's Lansana Fofana in the capital, Freetown, said the boat sank in heavy storms with traders, fishermen and about 70 children on board.
Operators in the area take very few safety precautions and are subject to no official monitoring, he says.
About 30 people are said to have been rescued since the disaster, and eight people have been confirmed dead so far.
"In addition local fishermen and other volunteers are all searching frantically at the scene of the disaster in the hope of rescuing more bodies," police spokesman Ibrahim Samura told the BBC's Network Africa programme.
But Mr Kargbo described the efforts more as a "recovery" mission now, as hopes of finding other survivors are slim.
He said that the cause of the accident seemed to suggest overcrowding.
"Eyewitnesses in Shenge said the boat was very small and it was forced to carry a very large amount of people," he said.
The boat was travelling a sea route of about 65km (40 miles) along the coast from the town of Shenge to the village of Tombo near Freetown.
It capsized not long after it left Shenge near Plantain Island.
Local journalist Edward Sesay in Tombo told the BBC News website the village was in a state of mourning as relatives wait for news.
One man had nine children on the boat who were returning to start the new school term.
The journalist says the boat's owner has not been found to comment on the accident.